Wikipedia
Olubadan
The Olubadan (Olubadan means Lord of Ibadan) is the royal title of the king of Ibadan land in Nigeria, now a largely symbolic role. Ibadan was founded in the 16th century, but the present Yoruba people only took control around 1820. By 1850 they had established their unusual succession principle, which is quite different compared with other traditional Yoruba rulers in that it alternates between two lines. It usually takes decades to groom an Olubadan for the stool through stages of chieftaincy promotion, thus meaning that just about any male born title-holder of the metropolitan center is a potential king.